dbacl is a digramic Bayesian text classifier.
Given some text, it calculates the posterior
probabilities that the input resembles one of any
number of previously learned document collections.
It can be used to sort incoming email into
arbitrary categories such as spam, work, and play,
or simply to distinguish an English text from a
French text. It fully supports international
character sets, and uses sophisticated statistical
models based on the Maximum Entropy Principle.

ddc-concordance is a search engine for linguists. It lets you search for
words or sequences of words together with morphological patterns. It was
created to help linguists find a particular collocation or word in a
given context.

dysii is a C++ library for distributed probabilistic inference and learning in large-scale dynamical systems. It provides methods such as the Kalman, unscented Kalman, and particle filters and smoothers, as well as useful classes such as common probability distributions and stochastic processes.

fanntool is a cross platform tool for the Fast
Artificial Neural Network (FANN) library. It can
detect the optimum parameters for an artificial
neural network (ANN). It allows you to adjust an
ANN's parameters easily, train with different
parameters, and test an ANN.

ffnet is a fast and easy-to-use feed-forward neural network training solution for Python. You can use it to train, test, save, load, and use an artificial neural network with sigmoid activation functions. Any network connectivity without cycles is allowed (not only layered). Training can be performed with several optimization schemes, including genetic alorithm based optimization. There is access to exact partial derivatives of network outputs versus its inputs. Normalization of data is handled automatically by ffnet.

fuzzylite is a fuzzy logic control library. Its goal is to allow you to easily create fuzzy logic controllers in a few steps utilizing object-oriented programming without requiring any third-party libraries. qtfuzzylite is a Qt-based GUI for fuzzylite. Its goal is to allow you to visually design your fuzzylite controllers and interact with them in real time.